The present invention relates to a device for providing a static and a dynamic seal between a rotatable shaft and a housing. In particular, the present invention relates to a seal device for inhibiting oil from leaking out of a housing and/or for inhibiting contaminants from traveling into the housing in severe splash conditions.
Prior art devices for sealing a rotating shaft are disclosed in U.S. Pat. No. 4,022,479 (Orlowski). Seal devices of this type may be used to inhibit oil from escaping out of a bearing housing and/or to inhibit contaminants from working their way into the housing. The prior art devices are formed of at least two ring-shaped members that rotate with respect to each other when the shaft is rotated. One of the members is fixed to the housing and does not rotate. The other member rotates with the rotating shaft.
The two ring members should be located very close together, particularly when the seal device is used to isolate the bearing from small particulate contaminants. Even small quantities of such contaminants are capable of significantly deteriorating the bearing. To inhibit such contamination, the two relatively rotatable ring members must be held together very closely, with only a very narrow space therebetween.
The ring members of the Orlowski seal device are connected together by a separate securing means, not shown in the prior art patent. The ring members themselves have no means for establishing and maintaining a narrow spacing therebetween. Therefore, the prior art seal device cannot be manufactured as a unit with a preset, fixed spacing. The spacing between the ring members has to be set when the seal device is installed into the housing. This leaves room for human error outside the control of the device manufacturer. In particular, the Orlowski device can be improperly installed, with the ring members located too far apart to perform satisfactorily. Another problem with the Orlowski device is that the ring members may be separated subsequent to installation, for example by high pressure cleaning spray.
Some prior art references refer to the use of a rotor and a stator, the latter including a plurality of alternating annular grooves and ridges and an axial groove. The grooves and ridges catch oil thrown by the rotating shaft. The oil then drains by gravity to the axial groove which allows the oil to travel back into the housing. One such reference, U.S. Pat. No. 5,522,601 (Murphy), refers to a locking labyrinth sealing assembly where a flange on a rotor wraps around and interlocks with a flange on a stator. The Murphy device, however, lacks an air-side opening and an oil-side opening which is sealed at the rotating shaft, making such a device susceptible to oil leakage in severe splash applications.
Other prior art references, such as, for example, U.S. Pat. No. 4,667,967 (Deuring), U.S. Pat. No. 4,065,136 (Miller) and U.S. Pat. No. 3,343,891 (Shipman) refer to sealing devices utilizing two or more pieces. Each of these seal devices lacks an air-side opening and an oil-side opening which is sealed at the rotating shaft. These types of seal devices may have deficiencies in applications where large amounts of oil can inundate the seals, such as in side-mounted pump bearing frames having double row thrust bearings where the seals are close to the bearings.
The problems of the prior art are overcome to a great extent by the present invention, which relates to a two-piece, interlocked labyrinth seal and a sealed system including a two-piece, interlocked labyrinth seal. The labyrinth seal includes a rotating member, such as a rotor, and a stationary member, such as a stator. The rotor includes a plurality of annular protrusions and annular grooves, and the stator interlocks with the rotor by way of an annular protrusion positioned within one of the rotor""s annular protrusions.
In accordance with a preferred embodiment of the present invention, the two-piece, interlocked labyrinth seal includes a rotor and a stator, both of which are adapted to completely encircle a rotating shaft.
In one aspect of the present invention, the stator includes an air-side opening located on the air side of the seal, an oil-side opening located on and sealed within the oil side of the seal, and a flange.
In another aspect of the invention, the stator includes a main portion and a cover. The air-side opening is located on the cover, and the oil-side opening and the flange are located on the main portion.
In another aspect of the invention, the stator includes an undersurface which faces one of two open ends of the oil-side opening.
In another aspect of the present invention, the rotor includes a slinger and a recess, and the stator includes a second annular protrusion positioned within the rotor recess.
In accordance with another preferred embodiment of the present invention, the stator includes an axial groove which extends to one of two open ends of the oil-side opening.
The foregoing and other advantages and features of the invention will be more readily understood from the following detailed description of the invention, which is provided in connection with the accompanying drawings.